High zeolite content and attrition resistant catalyst, methods for preparing the same and catalyzed processes therewith

ABSTRACT

A catalyst composition suitable for reacting hydrocarbons, e.g., conversion processes such as fluidized catalytic cracking (FCC) of hydrocarbons, comprises attrition resistant particulate having a high level (30-85%) of stabilized zeolites having a constraint index of 1 to 12. The stabilized zeolite is bound by a phosphorous compound, alumina and optional binders wherein the alumina added to make the catalyst is about 10% by weight or less and the molar ratio of phosphorous (P 2 O 5 ) to total alumina is sufficient to obtain an attrition index of about 20 or less. The composition can be used as a catalyst per se or as additive catalyst to a conventional catalyst and is especially suitable for enhancing yields of light olefins, and particularly ethylene, produced during conversion processes.

FIELD OF THE INVENTION

[0001] The present invention relates to an improved catalystcomposition, its manufacture, and a process for reacting hydrocarbonfeed over the improved catalyst.

BACKGROUND OF THE INVENTION

[0002] Processes such as catalytic cracking operations are commerciallyemployed in the petroleum refining industry to produce gasoline and fueloils from hydrocarbon-containing feeds. These cracking operations alsoresult in the production of useful lower olefins, e.g., C₃-C₅ olefins,and it has become increasingly desirable to maximize the yield of sucholefins from conversion process operations in general. Endothermiccatalytic cracking of hydrocarbons is commonly practiced in fluidcatalytic cracking (FCC) processes.

[0003] Generally, FCC is commercially practiced in a cyclic mode. Duringthese operations, the hydrocarbon feedstock is contacted with hot,active, solid particulate catalyst without added hydrogen, for example,at pressures of up to about 50 psig and temperatures up to about 650° C.The catalyst is a powder with particle sizes of about 20-200 microns indiameter and with an average size of approximately 60-100 microns. Thepowder is propelled upwardly through a riser reaction zone, fluidizedand thoroughly mixed with the hydrocarbon feed. The hydrocarbon feed iscracked at the aforementioned high temperatures by the catalyst andseparated into various hydrocarbon products. As the hydrocarbon feed iscracked in the presence of cracking catalyst to form gasoline andolefins, undesirable carbonaceous residue known as “coke” is depositedon the catalyst. The spent catalyst contains coke as well as metals thatare present in the feedstock. Catalysts for FCC are typically large porealuminosilicate compositions, including faujasite or zeolite Y.

[0004] The coked catalyst particles are separated from the crackedhydrocarbon products, and after stripping, are transferred into aregenerator where the coke is burned off to regenerate the catalyst. Theregenerated catalyst then flows downwardly from the regenerator to thebase of the riser.

[0005] These cycles of cracking and regeneration at high flow rates andtemperatures have a tendency to physically break down the catalyst intoeven smaller particles called “fines”. These fines have a diameter of upto 20 microns as compared to the average diameter of the catalystparticle of about 60 to about 100 microns. In determining the unitretention of catalysts, and accordingly their cost efficiency, attritionresistance is a key parameter. While the initial size of the particlescan be controlled by controlling the initial spray drying of thecatalyst, if the attrition resistance is poor, the catalytic crackingunit may produce a large amount of the 0-20 micron fines which shouldnot be released into the atmosphere. Commercial catalytic cracking unitsinclude cyclones and electrostatic precipitators to prevent fines frombecoming airborne. Those skilled in the art also appreciate thatexcessive generation of catalyst fines increases the cost of catalyst tothe refiner. Excess fines can cause increased addition of catalyst anddilution of catalytically viable particles.

[0006] Additionally, the catalyst particles cannot be too large indiameter, or the particles may not be sufficiently fluidized. Therefore,the catalysts are preferably maintained under 120 to 150 microns indiameter.

[0007] Particulated catalyst additives are also typically included inthe inventory of conventional large pore cracking catalysts for FCCprocesses and are therefore subject to the same attrition issues. Theseadditives are very useful in enhancing the properties of the resultinggasoline product as well as enhancing octane numbers of the gasolineproduct. Such additives also are especially suitable for enhancingyields of C₃-C₅ olefins. Those olefins are useful in making ethers andalkylates which are in high demand as octane enhances for gasoline, aswell as useful in making other chemical feedstocks.

[0008] Particulated catalysts and additives are prepared from a numberof compounds in addition to the primary active catalytic species. Forexample, the catalyst compositions can comprise clay and other inorganicoxides in addition to catalytically active ZSM-5. Alumina is oneparticular inorganic oxide other than zeolite that can be added. EP 256875 reports that alumina in conjunction with rare earth compoundsimproves hydrothermal stability and selectivity of zeolite Y.Phosphorous also is added to “stabilize” ZSM-5 containing catalysts.Additives sold as OlefinsMax™ by Grace Davison is an example.Stabilization of a catalyst composition means stabilizing the activityof the composition to produce higher yields of light olefins whencompared to a composition which has not been stabilized by phosphorus.This comparison is normally made after deactivation with steam.

[0009] U.S. Pat. No. 5,110,776 teaches a method for preparing FCCcatalyst comprising modifying the zeolite, e.g., ZSM-5, with phosphorus.U.S. Pat. No. 5,126,298 teaches manufacture of an FCC catalystcomprising zeolite, e.g., ZSM-5, clay, and phosphorus. See also WO98/41595 and U.S. Pat No. 5,366,948. Phosphorus treatment has been usedon faujasite-based cracking catalysts for metals passivation (see U.S.Pat. Nos. 4,970,183 and 4,430,199); reducing coke make (see U.S. Pat.Nos. 4,567,152; 4,584,091; and 5,082,815); increasing activity (see U.S.Pat. Nos. 4,454,241 and 4,498,975); increasing gasoline selectivity (SeeU.S. Pat. No. 4,970,183); and increasing steam stability (see U.S. Pat.Nos. 4,765,884 and 4,873,211).

[0010] In U.S. Pat. No. 3,758,403, use of large-pore cracking catalystwith large amounts of ZSM-5 additive gives only modest increase in lightolefin production. A 100% increase in ZSM-5 content (from 5 wt. % ZSM-5to 10 wt. % ZSM-5) increased the propylene yield less than 20%, anddecreased slightly the potential gasoline yield (C₅₊ gasoline plusalkylate).

[0011] When attempting to improve or enhance the catalytic activity ofthese compositions, the amounts of the various components in a catalystor catalyst additive and the relevant effect these components have onattrition have to be taken into account in order to maximize attritionresistance. The importance of attrition becomes increasingly acute when,for example, the ZSM-5 content of a catalyst is increased to enhance thecatalyst's activity. In certain instances, increasing a catalyst's ZSM-5content results in the use of less binder and matrix, and as a result,“softer” or more attrition prone particles can be created. Even thoughparticles having a ZSM-5 content up to 60% and an attrition index lessthan 20 have been reported (U.S. Pat. No. 5,366,948), it has beendifficult to prepare catalysts and additives which contain a greatmajority, i.e., greater than 60% of the active component over the othercomponents in the catalyst. For example, it would be desirable toincrease the amount of ZSM-5 to these high levels in certain catalystsin order to produce a particle which is more active in producing C₃-C₅olefin.

[0012] Refiners, e.g., FCC refiners, DCC (Deep Catalytic Cracking)refiners, as well as fixed fluidized bed refiners, would also find itadvantageous to enhance ethylene yields in order to maximize the yieldof valuable products from their refinery operations. Additives orcompositions comprising novel catalysts are potential avenues forenhancing ethylene yields. Using those additives or compositions,however, without materially affecting the yield of other olefins can bedifficult, especially in light of the other concerns mentioned abovewith respect to attrition.

[0013] Therefore, with certain refiners, it would not only be highlydesirable to prepare a catalyst composition having a high attritionresistance, it would also be desirable to provide catalyst compositionshaving improved activity for ethylene production as well assubstantially maintain the compositions' ability to produce otherolefins. Those skilled in the art will also appreciate that improvedattrition resistance as well as improved activity will translate intoreduced catalyst makeup rates.

[0014] Attrition resistance and high catalyst content would also benefitprocesses used to react hydrocarbons other than hydrocarbon crackingprocesses. Such processes include hydrocarbon isomerization,dimerization and the like.

SUMMARY OF THE INVENTION

[0015] It is an object of the present invention to provide an improvedcatalyst and an improved process using the same to chemically react ahydrocarbon feedstock.

[0016] Specifically, the invention is an attrition resistant zeolitecatalyst composition which has high levels of stabilized zeolite(30-85%) thereby effectively increasing the catalytic effect inreactions involving hydrocarbon feedstock. It has been unexpectedlydiscovered that by limiting the amount of alumina added to the catalystto 10% or less by weight of the catalyst and further maintaining aphosphorous content between about 6 and 24%, active catalysts containingup to 85% zeolite can be prepared. Acceptable Davison Attrition Indicesof 20 or less are achieved by further selecting a phosphorus (as P₂O₅)to total alumina molar ratio sufficient to maintain these attritionindices, while also maintaining acceptable activity, e.g., olefin yieldsin FCC. Suitable attrition properties are reflected by particles havingDavison index attrition numbers of 20 or lower, and preferably less than10.

[0017] The catalyst is especially effective for producing light C₃-C₅olefins (propylene and butylene) in hydrocarbon cracking processes, suchas those in a FCC Unit. The quantity of light olefins produced in a FCCunit is strongly affected by the amount of stabilized zeolite, e.g.,ZSM-5 or ZSM-11, in the unit and the unit conversion. Conversion isimportant since the amount of light olefins produced tends to increasewith unit conversion. The advantage of a catalyst which contains a highlevel of active zeolite is: 1) higher absolute amounts of active zeolitecan be put in the unit and/or 2) if the high content catalyst is used asan additive catalyst at constant ZSM-5 or ZSM-11 level, a lower quantityof additive is required and as a result there is less dilution of thestandard FCC catalyst, thereby allowing the unit to operate at higherconversion.

[0018] The invention also provides an improved phosphorus stabilizedcatalyst composition having a high content of active components, andsuitable attrition resistance, which is more selective towards producingethylene without significantly affecting total olefin yields exhibitedby conventional additives in FCC units.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIGS. 1-3 illustrates light olefin yields from a FCC processusing several embodiments of the inventive catalyst (40% by weightzeolite, 10% or less added alumina).

[0020]FIG. 4 illustrates the olefin yield of a FCC process using acomparison catalyst comprising more than 10% alumina.

[0021]FIG. 5 illustrates the effects of added alumina content onattrition resistance and propylene yield in a FCC catalyst.

[0022]FIG. 6 illustrates the percent change in olefin yield for theinvention relative to a conventional phosphorus stabilized ZSM-5catalyst. These results are taken at 70% conversion of the hydrocarbon.

[0023]FIG. 7 illustrates total wt. % olefin yield as a function ofcarbon number as compared against a conventional catalyst. These resultsare shown for 70% conversion level of the hydrocarbon. This figure aswell as FIG. 6 also show the effect the invention has in increasingethylene yield.

[0024]FIG. 8 illustrates the invention comprising 80% ZSM-5 and furtherillustrates how the molar ratio of phosphorous (P₂O₅) and aluminaaffects propylene yield.

[0025]FIG. 9 illustrates the propylene yield of an embodiment comprising80% ZSM-5 compared to a conventional catalyst on a ZSM-5 weight basisand catalyst basis.

[0026]FIG. 10 illustrates the ethylene yield for an embodimentcomprising 80% ZSM-5 compared to a conventional catalyst on both acatalyst and ZSM-5 weight basis.

DETAILED DESCRIPTION

[0027] The catalyst composition of this invention can be used, forexample, as the primary catalyst for a catalyzed reaction involvinghydrocarbon feedstock, as an additive to a fresh catalyst stream, or asan additive to an existing catalyst inventory. The catalyst is preparedfrom zeolite, alumina, phosphorous and optional additional components.

[0028] Zeolite

[0029] Commercially used zeolites having a Constraint Index of 1-12 canbe used for this invention. Details of the Constraint Index test areprovided in J. Catalysis, 67, 218-222 (1981) and in U.S. Pat. No.4,711,710 both of which are incorporated herein by reference.

[0030] Conventional shape-selective zeolites useful for this purpose areexemplified by intermediate pore (e.g., pore size of from about 4 toabout 7 Angstroms) zeolites. ZSM-5 (U.S. Pat. No. 3,702,886 and Re.29,948) and ZSM-11 (U.S. Pat. No. 3,709,979) are preferred. Methods forpreparing these synthetic zeolites are well known in the art.

[0031] Alumina

[0032] The alumina employed to make the invention is referred to hereinas “added alumina”. The added alumina component of the catalyst of thepresent invention therefore is defined herein as alumina separatelyadded to the slurry of starting components and dispersed in the matrixof the catalyst. The alumina primarily serves to act with phosphorous toform binder for the zeolite. Added alumina does not include aluminapresent in the other components of the additive, e.g., shape selectivezeolite or any clay used to prepare the additive. On the other hand, theterm “total alumina” as used herein refers to added alumina and aluminapresent in the other components.

[0033] Suitable added alumina includes particulate alumina having atotal surface area, as measured by the method of Brunauer, Emmett andTeller (BET) greater than 50 square meters per gram (m²/g), preferablygreater than 140 m²/g, for example, from about 145 to 400 m²/g.Preferably the pore volume (BET) of the particulate alumina will begreater than 0.35 cc/g. Such alumina may comprise a minor amount ofsilica or other inorganic oxides such as from about 0.1 to 15 weightpercent, preferably from about 0.1 to 6 weight percent silica, based onthe weight of the alumina component of the particles. The averageparticle size of the alumina particles will generally be less than 10microns, preferably less than 3 microns. Preferably, the porous aluminawill be bulk alumina. The term “bulk” with reference to the alumina isintended herein to designate a material which has been preformed andplaced in a physical form such that its surface area and porousstructure are stabilized so that when it is added to an inorganic matrixcontaining residual soluble salts, the salts will not alter the surfaceand pore characteristics measurably. Suitable particulate aluminasinclude, but are not limited to, CP3 from Alcoa and Catapal B fromCondea Vista.

[0034] Other suitable sources of added alumina include colloidal aluminaor alumina sols, reactive alumina, aluminum chlorhydrol and the like.

[0035] Phosphorus

[0036] Suitable phosphorus-containing compounds include phosphoric acid(H₃PO₄), phosphorous acid (H₃PO₃), salts of phosphoric acid, salts ofphosphorous acid and mixtures thereof. Ammonium salts such asmonoammonium phosphate (NH₄)H₂PO₄, diammonium phosphate (NH₄)₂HPO₃monoammonium phosphite (NH₄)H₂PO₃, diammonium phosphite (NH₄)₂HPO₃, andmixtures thereof can also be used. Other suitable phosphorous compoundsare described in WO 98/41595, the contents of which are incorporatedherein by reference. Those compounds include phosphines, phosphonicacid, phosphonates and the like.

[0037] Optional Inorganic Oxide

[0038] The catalyst of this invention can include suitable inorganicoxide matrices, such as non-zeolitic inorganic oxides, including silica,silica-alumina, magnesia, boria, titania, zirconia and mixtures thereof.The matrices may include one or more of various known clays, such asmontmorillonite, kaolin, halloysite, bentonite, attapulgite, and thelike. Most preferably, the inorganic oxide is a clay as described inU.S. Pat. No. 3,867,308; U.S. Pat. No. 3,957,689 and U.S. Pat. No.4,458,023. The matrix component may be present in the catalyst inamounts ranging from about 0 to about 60 weight percent. In certainembodiments, clay is preferably from about 10 to about 50 wt. % of thetotal catalyst composition;

[0039] It is also within the scope of the invention to incorporate inthe catalyst other materials such as other types of zeolites, clays,carbon monoxide oxidation promoters, etc.

[0040] In general, the catalyst of this invention is manufactured from aslurry of the components mentioned above. Suitable steps comprise:

[0041] (a) preparing an aqueous slurry comprising zeolite having aconstraint index of 1 to 12, phosphorus-containing compound, alumina andoptionally, matrix comprising clay, etc., in amounts which will resultin a final dried product of step (b) having from about 30-85% ZSM-5 orZSM-11, no more than 10% by weight added alumina, about 6-24% by weightphosphorous (as measured P₂O₅) and no more than 30% by weight totalalumina;

[0042] (b) spray drying the slurry of step (a) at a low pH, such as a pHof less than about 3, preferably less than about 2; and

[0043] (c) recovering a spray-dried product having attrition propertiesas evidenced by a Davison Index of 20 or less.

[0044] Methods for slurrying, milling, spray drying and recoveringparticles suitable as a catalyst or additive are known in the art. SeeU.S. Pat. No. 3,444,097 as well as WO 98/41595 and U.S. Pat. No.5,366,948. The catalyst particle size should be in the range of 20-200microns, and have an average particle size of 60-100 microns.

[0045] As indicated above, the amount of added alumina is 10% or less byweight of the total components making up the particles, with particlescomprising 3-8% added alumina being most preferable for FCC processes interms of the resulting attrition properties and olefin yield.

[0046] Molar Ratio of Phosphorous (P₂O₅)/Total Alumina

[0047] The phosphorus/total alumina ratio, wherein the phosphorous ismeasured as P₂O₅, is selected to obtain particles that have an attritionindex of about 20 or less. The ratio is also selected to optimize olefinyield. This ratio is calculated using standard techniques and is readilycalculated from the amounts of phosphorous added and total aluminapresent in the additive. The examples below illustrate methods forobtaining the appropriate ratios. As indicated earlier, total aluminaincludes added alumina and alumina that may be present in othercomponents, i.e., non-added alumina. Total alumina can be measured bybulk analysis.

[0048] Ratios for obtaining suitable attrition resistance and preferredactivity is dependent upon the content of zeolite. Generally, the higherthe zeolite content, the larger the ratio used. Generally suitableratios, as well as preferred ratios to obtain attrition indices of about10 or less, are indicated below. All other ranges of ratios within thesuitable ranges are also contemplated, e.g., 0.4 to 1.0, 0.25 to 0.7,etc. Zeolite Content Suitable Ratio Preferred Ratio   30-60% zeolite 0.2to 1.0 0.25 to 0.70 >60-85% zeolite 0.2 to 1.9 0.45 to 1.0

[0049] In general, the amount of phosphorus is selected to sufficientlyharden the particle without causing a loss in activity in terms ofolefin yield. The sufficient amount of phosphorus for this purpose isfrom about 6 to about 24% of the total composition. The amount ofphosphorus can also be in all other ranges contained within the range of6-24%, e.g., 7-23%, 7-15%, etc.

[0050] As illustrated in FIG. 5, alumina affects olefin yield andattrition, and it is shown that 10% or less added alumina provides abalance of those properties. The ratios above are therefore a reflectionof the effects alumina and phosphorus have on the resulting particles'properties.

[0051] The Davison Attrition Index is used to measure attrition of theadditive. To determine the Davison Attrition Index (DI) of thecatalysts, 7.0 cc of sample catalyst is screened to remove particles inthe 0 to 20 micron range. Those particles are then contacted in ahardened steel jet cup having a precision bored orifice through which anair jet of humidified (60%) air is passed at 21 liter/minute for 1 hour.The DI is defined as the percent of 0-20 micron fines generated duringthe test relative to the amount of >20 micron material initiallypresent, i.e., the formula below.${DI} = {100 \times \frac{{wt}\quad \% \quad {of}\quad 0{–20}\quad {micron}\quad {material}\quad {formed}\quad {during}\quad {test}}{{{wt}.\quad {of}}\quad {original}\quad 20\quad {microns}\quad {or}\quad {greater}\quad {material}\quad {before}\quad {test}}}$

[0052] The lower the DI number, the more attrition resistant is thecatalyst. Commercially acceptable attrition resistance is indicated by aDI of less than about 20, and preferably less than 10.

[0053] Hydrocarbon Conversion Processes

[0054] As discussed earlier, the invention is suitable for any chemicalreaction involving a hydrocarbon feed requiring catalyst to facilitatethe reaction. Such reactions include hydrocarbon conversion processesinvolving molecular weight reduction of a hydrocarbon, e.g., cracking.The invention can also be employed in isomerization, dimerization,polymerization, hydration and aromatization. The conditions of suchprocesses are known in the art. See U.S. Pat. No. 4,418,235 incorporatedherein by reference. Other applicable processes include upgradings ofreformate, transalkylation of aromatic hydrocarbons, alkylation ofaromatics and reduction in the pour point of fuel oils. For the purposesof this invention, “hydrocarbon feedstock” not only includes organiccompounds containing carbon and hydrogen atoms, but also includeshydrocarbons comprising oxygen, nitrogen and sulfur heteroatoms. Thefeedstocks can be those having a wide range of boiling temperatures,e.g., naphtha, distillate, vacuum gas oil and residual oil. Suchfeedstocks also include those for making heterocyclic compounds such aspyridine.

[0055] The invention is particularly suitable for fluidized processes,e.g., in which catalyst attrition is a factor. The invention isespecially suitable for fluidized catalytic cracking of a hydrocarbonfeed to a mixture of products comprising gasoline, alkylate, potentialalkylate, and lower olefins, in the presence of conventional crackingcatalyst under catalytic cracking conditions.

[0056] Typical hydrocarbons, i.e., feedstock, to such processes mayinclude in whole or in part, a gas oil (e.g., light, medium, or heavygas oil) having an initial boiling point above about 204° C., a 50%point of at least about 260° C., and an end point of at least about 315°C. The feedstock may also include deep cut gas oil, vacuum gas oil,thermal oil, residual oil, cycle stock, whole top crude, tar sand oil,shale oil, synthetic fuel, heavy hydrocarbon fractions derived from thedestructive hydrogenation of coal, tar, pitches, asphalts, hydrotreatedfeedstocks derived from any of the foregoing, and the like. As will berecognized, the distillation of higher boiling petroleum fractions aboveabout 400° C. must be carried out under vacuum in order to avoid thermalcracking. The boiling temperatures utilized herein are expressed interms of convenience of the boiling point corrected to atmosphericpressure. Resids or deeper cut gas oils having an end point of up toabout 700° C., even with high metals contents, can also be cracked usingthe invention.

[0057] Catalytic cracking units are generally operated at temperaturesfrom about 400° C. to about 650° C., usually from about 450° C. to about600° C., and under reduced, atmospheric, or superatmospheric pressure,usually from about atmospheric to about 5 atmospheres.

[0058] An FCC catalyst (primary or additive) is added to a FCC processas a powder (20-200 microns) and generally is suspended in the feed andpropelled upward in a reaction zone. A relatively heavy hydrocarbonfeedstock, e.g., a gas oil, is admixed with a catalyst to provide afluidized suspension and cracked in an elongated reactor, or riser, atelevated temperatures to provide a mixture of lighter hydrocarbonproducts. The gaseous reaction products and spent catalyst aredischarged from the riser into a separator, e.g., a cyclone unit,located within the upper section of an enclosed stripping vessel, orstripper, with the reaction products being conveyed to a productrecovery zone and the spent catalyst entering a dense catalyst bedwithin the lower section of the stripper. After stripping entrainedhydrocarbons from the spent catalyst, the catalyst is conveyed to acatalyst regenerator unit. The fluidizable catalyst is continuouslycirculated between the riser and the regenerator and serves to transferheat from the latter to the former thereby supplying the thermal needsof the cracking reaction which is endothermic.

[0059] Gas from the FCC main-column overhead receiver is compressed anddirected for further processing and separation to gasoline and lightolefins, with C₃ and C₄ product olefins being directed to apetrochemical unit or to an alkylation unit to produce a high octanegasoline by the reaction of an isoparaffin (usually iso-butane) with oneor more of the low molecular weight olefins (usually propylene andbutylene). Ethylene would be recovered in a similar fashion andprocessed to additional petrochemical units.

[0060] The FCC conversion conditions include a riser top temperature offrom about 500° C. to about 595° C., preferably from about 5200 C. toabout 565° C., and most preferably from about 530° C. to about 550° C.;catalyst/oil weight ratio of from about 3 to about 12, preferably fromabout 4 to about 11, and most preferably from about 5 to about 10; andcatalyst residence time of from about 0.5 to about 15 seconds,preferably from about 1 to about 10 seconds.

[0061] The catalyst of this invention is suitable as a catalyst alone,or as an additive to cracking processes which employ conventionallarge-pore molecular sieve component. The same applies for processesother than cracking processes. Cracking catalysts are large porematerials having pore openings of greater than about 7 Angstroms ineffective diameter. Conventional large-pore molecular sieve includezeolite X (U.S. Pat. No. 2,882,442); REX; zeolite Y (U.S. Pat. No.3,130,007); Ultrastable Y (USY) (U.S. Pat. No. 3,449,070); Rare Earthexchanged Y (REY) (U.S. Pat. No. 4,415,438); Rare Earth exchanged USY(REUSY); Dealuminated Y (DeAl Y) (U.S. Pat. Nos. 3,442,792 and4,331,694); Ultrahydrophobic Y (UHPY) (U.S. Pat. No. 4,401,556); and/ordealuminated silicon-enriched zeolites, e.g., LZ-210 (U.S. Pat. No.4,678,765). Preferred are higher silica forms of zeolite Y. ZSM-20 (U.S.Pat. No. 3,972,983); zeolite Beta (U.S. Pat. No. 3,308,069); zeolite L(U.S. Pat. Nos. 3,216,789 and 4,701,315); and naturally occurringzeolites such as faujasite, mordenite and the like may also be used(with all patents above in parentheses incorporated herein byreference). These materials may be subjected to conventional treatments,such as impregnation or ion exchange with rare earths to increasestability. In current commercial practice most cracking catalystscontain these large-pore molecular sieves. The preferred molecular sieveof those listed above is a zeolite Y, more preferably an REY, USY orREUSY. Supemova™ D Catalyst from Grace Davison is a particularlysuitable large pore catalyst. Methods for making these zeolites areknown in the art.

[0062] Other large-pore crystalline molecular sieves include pillaredsilicates and/or clays; aluminophosphates, e.g., ALPO₄-5, ALPO₄-8,VPI-5; silicoaluminophosphates, e.g., SAPO-5, SAPO-37, SAPO-40, MCM-9;and other metal aluminophosphates. Mesoporous crystalline material foruse as the molecular sieve includes MCM-41. These are variouslydescribed in U.S. Pat. Nos. 4,310,440; 4,440,871; 4,554,143; 4,567,029;4,666,875; 4,742,033; 4,880,611; 4,859,314; 4,791,083; 5,102,643; and5,098,684, each incorporated herein by reference.

[0063] The large-pore molecular sieve catalyst component may alsoinclude phosphorus or a phosphorus compound for any of the functionsgenerally attributed thereto, such as, for example, attritionresistance, stability, metals passivation, and coke make reduction.

[0064] As illustrated and described in more detail in the followingexamples, it has been discovered that by using 10% or less by weight ofadded alumina, one can prepare suitable attrition resistant and activecatalyst particles comprising high content, i.e., 30-85%, zeolite. Theinventive catalysts are also more selective for ethylene, withoutsubstantially reducing the total light olefin, e.g., propylene, yieldsfrom catalysts and additives being used commercially, e.g., thosecontaining about 25% ZSM-5. In certain embodiments illustrated below,the olefin yield of the invention as measured by propylene yield wasequal (on a ZSM-5 basis) to that of conventional phosphorus stabilizedZSM-5 catalysts.

[0065] The activity of the invention on a ZSM-5 basis in a FCC unit,relative to OlefinsMax additive, is in the range of about 40 to 100% interms of propylene yields per the MAT test of ASTM 3907. This activityis based on measurements at a constant conversion, e.g., 70%, and as acatalyst additive to Grace's Supernova D faujasite catalyst. Preferredcatalysts are at least 50% as active, and more preferably have activityin the range of 70-100% as active as OlefmsMax. As illustrated in theexamples below, the invention can be as active, or two or three timesmore active than OlefinsMax additive on a particle basis.

[0066] Indeed, it is believed that attrition resistant and phosphorusstabilized active catalysts having such zeolite, e.g., ZSM-5 or ZSM-11,contents greater than 60% zeolite, and particularly up to 85% by weightzeolite, have heretofore not been made. It is believed that limiting theamount of alumina to 10% or less and then optimizing the ratio ofphosphorus to total alumina allows one to make such catalysts. Inaddition to the benefits already noted above, these high contentadditives allow one to supplement existing catalyst inventories withzeolite catalysts having the desired activity and attrition while at thesame time minimizing the amount of non-zeolite material (such as matrix)to the catalyst inventory.

[0067] The following examples are provided for illustrative purposes andare not intended to limit in any way the scope of the claims appendedhereto. Percentages described below are those by weight (wt.). The ratioof P₂O₅/Al₂O₃ below reflects the molar ratio of phosphorus to totalalumina in the catalyst. The abbreviations mentioned in the Examplesbelow are defined as follows.

[0068] BET—Refers to the surface area measured by the Brunauer, Emmettand Teller method of using nitrogen porosity to measure surface area

[0069] Atm—Atmosphere

[0070] DI—Davison Index

[0071] ICP—Inductively Coupled Plasma

[0072] LCO—Light Cycle Oil

[0073] HCO—Heavy Cycle Oil

[0074] m—meter

[0075] g—gram

EXAMPLES Example 1 Preparation of 40% ZSM-5/6.5% Al₂O₃ Catalyst

[0076] An aqueous slurry containing 800 g of ZSM-5 (26:1 molar ratio ofSiO₂ to Al₂O₃) (dry basis), 830 g clay (dry basis), 130 g of Catapal BAl₂O₃ (dry basis) and 357 g of concentrated H₃PO₄ were blended and mixedat a 45% solids level. The slurry was then milled in a Drais mill andspray-dried in a Bowen spray-drier to prepare Sample A. Two additionalpreparations were made in the same manner, and were labeled Samples Band C, where the P₂O₅ and clay levels were varied as shown below:

[0077] A. 40% ZSM-5/6.5% Catapal B/11% P₂O₅/42.5% clay

[0078] B. 40% ZSM-5/6.5% Catapal B/12% P₂O₅/41.5% clay

[0079] C. 40% ZSM-5/6.5% Catapal B/13.5% P₂O₅/40% clay

[0080] The resulting materials were then calcined for 2 hours @ 1000° F.and analyzed by ICP, T-plot surface area, and DI attrition. The chemicaland physical characterization data for Samples A-C is shown in Table Ibelow. The catalysts have DI attrition numbers between 11 and 15. TABLE1 Sample A B C Formulation ZSM-5 40 40 40 P₂O₅ 11 12 13.5 Al₂O₃ 6.5 6.56.5 Clay 42.5 41.5 40 Total 100 100 100 Physical Properties 2 hours @1000° F. 13 15 11 DI Al₂O₃ 26.14 25.9 25.87 P₂O₅ 11.6 11.95 13.6 SiO₂57.16 56.53 57.39 P₂O₅/Al₂O₃ 0.32 0.33 0.38 Total BET Surface 137 132118 Area

Example 2 Microactivitv Testing of Example 1 Catalysts

[0081] The calcined catalysts in Example 1 were deactivated by steamingfor 4 hours at 1500° F./100% steam in a fluidized bed steamer. Thesamples were then blended at a 2.5% additive level with a steamdeactivated Super Nova™D (Davison commercial cracking catalyst, 2.5%Re₂O₃ on catalyst). The admixture was used to crack Feed A (Propertiesin Table 2) in a Microactivity Test (MAT) as set forth in ASTM 3907.TABLE 2 Feed A Feed B API Gravity @ 60° F. 22.5 23.9 Aniline Point, ° F.163 198 Sulfur, wt. % 2.59 0.733 Total Nitrogen, wt. % 0.086 0.1 BasicNitrogen, wt. % 0.034 0.042 Conradson Carbon, wt. % 0.25 0.33 ASTMD-2887 Simdist IBP 423 464  5 585 592 10 615 637 20 649 693 30 684 73040 720 772 50 755 806 60 794 844 70 834 883 80 881 927 90 932 977 95 9761018 FBP 1027 1152

[0082] The base case catalysts tested with these samples included: 1)steam deactivated Super Nova D™(SND) and 2) 96% steam deactivated SNDblended with 4% steam deactivated conventional catalysts additiveavailable as OlefinsMax™ from Davison which contains 25% of a phosphorusstabilized ZSM-5. The OlefinsMax and SND compositions were deactivatedseparately, each for 4 hours at 1500° F./100% steam in a fluidized bedsteamer.

[0083] The propylene yield (wt. % of feed) as a function of wt. %conversion is shown in FIG. 1. The data shows that on an equal ZSM-5level (1% ZSM-5), the propylene yield of the catalyst containing Example1, Sample B, is equal to the sample containing OlefinsMax.

Example 3 Preparation of 40% ZSM-5/8% Al₂O₃ Catalysts

[0084] Catalysts were prepared in the same manner as Example 1 exceptwith the following compositions:

[0085] D. 40% ZSM-5/8% Catapal B/11.5% P₂O₅/40.5% clay

[0086] E. 40% ZSM-5/8% Catapal B/13% P₂O₅/39% clay

[0087] F. 40% ZSM-5/8% Catapal B/14.5% P₂O₅/37.5% clay

[0088] The resulting samples were calcined for 2 hours @1000° F. andanalyzed by ICP, T-plot surface area, and DI attrition. The chemical andphysical characterization data is shown in Table 3. The catalysts haveDI attrition numbers between 8 and 9. TABLE 3 Sample D E F FormulationZSM-5 40 40 40 P₂O₅ 11.5 13 14.5 Al₂O₃ 8 8 8 Clay 40.5 39 37.5 Total 100100 100 Physical Properties 2 hours @ 1000° F. DI 9 8 8 Al₂O₃ 27.5727.64 26.81 P₂O₅ 12.4 13.62 14.72 SiO₂ 57.57 56.24 57.8 P₂O₅/Al₂O₃ 0.320.35 0.38 Total BET Surface 126 125 118 Area

Example 4 Microactivity Testing of Example 3 Catalysts

[0089] The calcined catalysts in Example 3 were deactivated by steamingfor 4 hours at 1500° F./100% steam in a fluidized bed steamer. Thematerial was then blended at a 2.5% additive level with a steamdeactivated Super Nova® D cracking catalyst, 2.5% Re₂O₃ on catalyst. Theadmixture was used to crack Feed A in a Microactivity Test (MAT) as setforth in ASTM 3907. The base case catalysts tested with these samplesincluded: 1) steam deactivated SND and 2) 96% steam deactivated SNDblended with 4% steam deactivated OlefinsMax. The OlefinsMax and SNDcatalysts were steam deactivated separately, each for 4 hours at 1500°F./100% steam in a fluidized bed steamer.

[0090] The propylene yield (wt. % of feed) as a function of wt. %conversion is shown in FIG. 2. The data shows that when compared on anequal ZSM-5 basis (1% ZSM-5), the catalysts containing Sample D andSample E produce 85% of the propylene produced using OlefinsMaxadditive. Sample F produces 80% of the propylene of OlefinsMax.

Example 5 Preparation of 40% ZSM-5/10% Al₂O₃ Catalyst

[0091] Catalysts were prepared in the same manner as Example 1 exceptwith the following compositions:

[0092] G. 40% ZSM-5/10% Catapal B/13% P₂O₅/37% clay

[0093] H. 40% ZSM-5/10% Catapal B/14% P₂O₅/36% clay

[0094] I. 40% ZSM-5/10% Catapal B/15% P₂O₅/35% clay

[0095] The resulting materials were calcined for 2 hours @1000° F. andanalyzed by ICP, T-plot surface area, and Davison index attrition. Thechemical and physical characterization data is shown in Table 4. Thecatalysts have DI attrition numbers between 2 and 3. TABLE 4 Sample G HI Formulation ZSM-5 40 40 40 P₂O₅ 13 14 15 Al₂O₃ 10 10 10 Clay 37 36 35Total 100 100 100 Physical Properties 2 hours @ 1000° F. DI 2 2 3P₂O₅/Al₂O₃ 0.33 0.36 0.39 Total BET 141 134 131 Surface Area

Example 6 Microactivity Testing of Example 5 Catalysts

[0096] The calcined catalysts in Example 5 were deactivated by steamingfor 4 hours at 1500° F./100% steam in a fluidized bed steamer. Thematerial was then blended at a 2.5% additive level with a steamdeactivated Super Nova® D cracking catalyst, 2.5% Re₂O₃ on catalyst. Theadmixture was used to crack Feed A in a Microactivity Test (MAT) as setforth in ASTM 3907. The base case catalysts tested with these samplesincluded: 1) steam deactivated SND and 2) 96% steam deactivated SNDblended with 4% steam deactivated OlefinsMax additive. The OlefinsMaxand SND catalysts were steam deactivated separately, each for 4 hours at1500° F./100% steam in a fluidized bed steamer.

[0097] The propylene yield (wt. % of feed) as a function of wt. %conversion is shown in FIG. 3. The data shows that when compared on anequal ZSM-5 basis (1% ZSM-5), the catalysts containing Sample I produces75% of the propylene of OlefinsMax. Sample G and Sample H produce 70% ofthe propylene of OlefinsMax.

Example 7 Preparation of 40% ZSM-5/20% Al₂O₃ Catalysts (Comparison)

[0098] Catalysts were prepared in the same manner as Example 1 exceptwith the following compositions:

[0099] J. 40% ZSM-5/20% Al₂O₃/20% P₂O₅/20% clay

[0100] K. 40% ZSM-5/20% Al₂O₃/28% P₂O₅/12% clay

[0101] L. 40% ZSM-5/20% Al₂O₃/35% P₂O₅/5% clay

[0102] The resulting materials were calcined for 2 hours @1000° F. andanalyzed by ICP, T-plot surface area, and DI attrition. The chemical andphysical characterization data is shown in Table 5. The catalysts haveDI attrition numbers between 5 and 9. TABLE 5 Sample J K L FormulationZSM-5 40 40 40 P₂O₅ 20 28 35 Clay 20 12 5 Al₂O₃ 20 20 20 Total 100 100100 Physical Properties DI 7 9 5 Al₂O₃ 29.85 26.9 24.41 P₂O₅ 20.53 27.9734.26 SiO₂ 49.07 43.1 41.74 P₂O₅/Al₂O₃ ratio 0.49 0.75 1.01 Total BET147 112 44 Surface Area

Example 8 Microactivity Testing of Example 7 Comparison Catalysts

[0103] The calcined catalysts in Example 7 were deactivated by steamingfor 4 hours at 1500° F./100% steam in a fluidized bed steamer. Thematerial was then blended at a 4% additive level with a steamdeactivated Super Nova® D cracking catalyst, 2.5% Re₂O₃ on catalyst. Theadmixture was used to crack Feed A in a Microactivity Test (MAT) as setforth in ASTM 3907. The base case catalysts tested with these samplesincluded: 1) steam deactivated SND and 2) 93.6% steam deactivated SNDblended with 6.4% steam deactivated OlefinsMax additive. The OlefinsMaxand SND catalysts were steam deactivated separately, each for 4 hours at1500° F./100% steam in a fluidized bed steamer.

[0104] The propylene yield (wt. % of feed) as a function of wt. %conversion is shown in FIG. 4. While the additive has suitable attritionresistance, the data shows that for these catalysts when compared on anequal ZSM-5 basis (1.6% ZSM-5), were relatively less active than thoseof Examples 1, 3, and 5 which contained added alumina of 6.5, 8 and 10%by weight, respectively.

Example 9 Effect of Added Al₂O₃ on Propylene Yield

[0105] The data from Examples 1-8 illustrate a correlation between theamount of added Al₂O₃ in the ZSM-5 (40% by weight) catalyst and therelative propylene yield. The propylene yield is measured as a percentof propylene produced relative to OlefmsMax (equal ZSM-5 level) at 70%conversion. $\begin{matrix}{{Relative}\quad {Propylene}} \\{Yield}\end{matrix} = {100\% \times \frac{\left\lbrack {{{Propylene}\quad ({Example})} - {{Propylene}\quad \left( {{SND}\quad {Base}\quad {Catalyst}} \right)}} \right\rbrack}{\left\lbrack {{{Propylene}\quad ({OlefinsMax})} - {{Propylene}\quad \left( {{SND}\quad {Base}\quad {Catalyst}} \right)}} \right\rbrack}}$

[0106] The propylene yield data for each catalyst used in thecorrelation was based on the best performance achieved for that catalyst(optimized P₂O₅ level). The correlation is shown in FIG. 5 whichindicates that as the added Al₂O₃ in the catalyst decreases, thepropylene yield increases. At added Al₂O₃ levels below 10%, thepropylene yield increases dramatically. At matrix Al₂O₃ levels between 3and 8%, the 40% ZSM-5 catalyst becomes equal in activity to OlefinsMaxwhen compared on an equivalent ZSM-5 basis.

[0107] Also shown in FIG. 5 are the DI attrition numbers for thecatalyst as a function of added Al₂O₃. The data shows that the attritionnumbers tend to increase as the added Al₂O₃ content decreases. However,it was discovered that if the amount of alumina added to the slurry ofstarting components for the catalyst was such that the final catalysthad less than 10% by weight added alumina, acceptable propylene and lowattrition numbers were produced.

Example 10 Selectivity of Invention for Ethylene

[0108] The calcined material in of Sample B (Example 1) was deactivatedby steaming for 4 hours at 1500° F. in a fluidized bed steamer. Thematerial was then blended at a 10 (4% ZSM-5), 20 (8% ZSM-5) and 32%(12.8% ZSM-5) additive level with an equilibrium catalyst (ECAT). Theadmixture was then used to crack Feed B (properties in Table 2) in aMicroactivity (MAT) test as set forth in ASTM 3907. OlefinsMaxdeactivated in the identical manner and mixed with the same ECAT, wastested at the 16% (4% ZSM-5) and 32% (8% ZSM-5) additive levels as acomparison. The cracking temperature used in this experiment was 1050°F. instead of the standard 980° F. A sample containing 100% ECAT wasalso tested as a control. The analysis of the ECAT appears below. ECATAnalyses Al₂O₃, wt. % 44.4 Na₂O, wt. % 0.37 RE₂O₃, wt. % 0.83 V, ppm1892 Ni, ppm 2788 Unit Cell Size, Å 24.25 BET Surface Area, m²/g 171

[0109] The interpolated hydrocarbon yields at 70% conversion are shownin Table 6. At equal ZSM-5 levels, the 40% additive increases the amountof ethylene, shows relatively equal propylene and lower C₄-olefins ascompared to OlefinsMax. An analysis of C₂-C₉ olefins in the samplesindicates that there was some decrease in C₅ olefins (FIGS. 6 and 7).TABLE 6 Constant Conversion Table Feed B; 1050° F. Conversion: 70%Additive ECAT 16% OlefinsMax 10% Invention 32% OlefinsMax 20% Invention32% Invention ZSM-5, Wt. % 0 4 4 8 8 12.8 (Example 1, Sample B) Cat/oil3.4 3.9 3.8 4.4 3.8 4.2 Hydrogen 0.18 0.17 0.18 0.17 0.18 0.17 Methane0.82 0.81 0.82 0.81 0.87 0.84 Tot C1 + C2 2.47 3.73 4.02 4.73 5.18 5.80C2= 0.99 2.22 2.48 3.20 3.55 4.19 Dry Gas 2.67 3.96 4.26 5.00 5.46 6.11C3= 5.57 12.88 12.86 14.25 13.97 14.17 C3 0.93 1.73 1.89 2.09 2.40 2.66Total C3's 6.56 14.61 14.75 16.29 16.39 16.83 Total C4= 7.04 10.78 10.3911.19 10.68 10.70 iC4 3.34 4.52 4.63 4.38 5.10 4.58 nC4 0.68 0.93 0.981.03 1.21 1.24 Total C4s 11.13 16.23 16.12 16.66 16.87 16.48 Light Gas20.30 34.57 34.92 37.89 38.54 39.22 C5 + Gaso 46.78 32.82 31.52 29.0228.77 27.57 LCO 20.78 19.83 19.64 19.71 20.18 19.38 HCO 9.22 10.17 10.3210.26 9.82 10.58 Coke, wt. % 2.72 2.60 3.19 2.80 2.87 2.75

Example 11 Very High (80%) ZSM-5 Content Catalysts

[0110] Catalysts having the composition indicated in Table 7 for SamplesM-P were prepared in the same manner as in Example 1. As with the otherexamples, the resulting materials were calcined for two hours at 1000°F. and analyzed for ICP, T-plot surface area, and DI attrition. Thisdata is also reflected in Table 7, below.

[0111] This example illustrates that very high ZSM-5 content catalystswhich are relatively attrition resistant can be made according to theinvention. The following Example 12 shows that the activity of thecatalyst can be optimized with suitable phosphorus to total aluminaratio. TABLE 7 Physical and Chemical Properties of 80% ZSM-5 CatalystSample M N O P ZSM-5 80 80 80 80 P₂O₅ 11.6 12.5 12.9 13.2 Aluminumchlorhydrol 8.4 7.5 7.1 6.8 Total 100 100 100 100 Physical Properties 2hours @ 1000° F. 0.67 0.78 0.83 0.88 P₂O₅/Al₂O₃ DI 21 5 3 3 Total BETSurface Area, m²/g 318 316 287 276

Example 12 Microactivity Testing for Very High ZSM-5 Content Catalysts

[0112] The calcined catalysts in Example 11 were deactivated as with theother examples by steaming for four hours at 1500° F./100% steam in afluidized bed steamer. The samples were then blended at a 2.5% additivelevel with a steam deactivated Super Nova® D cracking catalysts, 2.5%Re₂O₃ on catalysts and used to crack Feed A. The feed was tested as setforth in ASTM 3907. The activity results from these tests on a ZSM-5basis (1% ZSM-5) are in FIG. 8.

[0113] As illustrated by the propylene yields (as a weight percentage offeed) in FIG. 8, the phosphorous to total alumina ratio for theinvention can be modified to obtain the desired propylene yields fromthe very high ZSM-5 content catalyst, i.e., 80% ZSM-5.

Example 13 Activity of High Zeolite Content Catalysts on Catalyst Basis

[0114] A catalyst having the composition indicated in Table 8 below wasprepared in the manner described in Example 1 and was tested foractivity to illustrate the activity on a catalyst particle basis. Theprevious examples illustrated the activity on a zeolite basis. TABLE 8Physical and Chemical Properties of 80% ZSM-5 Catalyst Sample Q ZSM-5 79P₂O₅ 14 Al₂O₃ 2 Clay 0 Aluminum chlorhydrol 5 Total 100 PhysicalProperties 2 hours @ 1000° F. 9 DI Al₂O₃, wt. % 11.5 P₂O₅, wt. % 14.23SiO₂, wt. % 76.06 P₂O₅/Total Al₂O₃ 0.89 Total BET Surface Area, m²/g 263

[0115]FIG. 9 illustrates that the high content catalyst (Catalyst Q inTable 8) on an equal catalyst (=Cat) basis is more active than the priorart OlefinMax (OMax) additive. As mentioned earlier, suitable catalysts(Cat) having a higher activity on a catalyst basis have been difficultto make because of increased attrition occurring in additives containingmore than 25% ZSM-5. The data illustrated in FIG. 9 is found in Table 9below. An equilibrium catalyst (ECAT) was also tested as a comparisonbase catalyst. ECAT is the same equilibrium catalyst referred to earlierin Example 10.

[0116]FIG. 10 illustrates the specific activity of Catalyst Q forproducing ethylene compared to the 25% ZSM-5 additive. FIG. 10illustrates that the high zeolite content catalyst not only hassubstantially the same activity for producing ethylene on an equal ZSM-5(=ZSM) basis, but also has higher activity for ethylene on a catalystbasis. These figures indicate that the high zeolite content catalystsoffer significant advantages for refiners seeking to enhance ethyleneyields. TABLE 9 Interpolated Yields from Catalyst Q Compared toOlefinsMax on an Equal ZSM-5 and Equal Catalyst Basis Additives Blendedwith ECAT at a 1% ZSM-5 level and a 4% Additive level; SIHGO Gas OilConversion 70 Catalyst Catalyst ECAT OMAX Q (= ZSM) Q (= CAT) Catalystto Oil Ratio 4.49 4.35 4.44 4.16 Hydrogen 0.30 0.28 0.30 0.27 Methane0.74 0.65 0.67 0.64 Ethylene 0.74 1.18 1.05 1.65 Tot C1 + C2 2.08 2.372.27 2.84 Dry Gas 2.37 2.65 2.57 3.11 Propylene 4.27 8.77 7.69 9.84Propane 0.95 1.54 1.39 1.96 Total C3's 5.22 10.31 8.98 11.80 1-Butene1.28 1.63 1.50 1.64 Isobutylene 1.35 2.54 2.15 3.15 Trans-2-butene 1.652.10 1.96 2.12 Cis-2-butene 1.30 1.66 1.54 1.66 Total C4 = s 5.58 7.937.15 8.58 IsoButane 3.92 5.79 5.34 6.50 n-C4 0.82 1.02 0.96 1.21 TotalC4s 10.31 14.73 13.46 16.28 Wet Gas 17.91 27.69 25.02 31.19 Gasoline47.10 37.07 39.34 33.18 LCO 24.88 24.49 24.65 24.18 Bottoms 5.12 5.515.35 5.82 Coke 4.98 5.24 5.64 5.62

Example 14 Attrition and Activity Versus Molar Ratio of Phosphorus(P₂O₅) and Total Alumina

[0117] Additives were prepared according to the invention using theamounts of components indicated in Tables 10, 11, and 12. The additiveswere prepared using the preparation methods described in Example 1. Asindicated in the tables, the molar ratio of phosphorus (measured asP₂O₅) to total alumina was varied for additives comprising 60, 70 andabout 80% ZSM-5.

[0118] Catalyst R-W comprising the components indicated in Table 10below comprise 60% by weight ZSM-5 and either 7% added alumina or 9%added alumina. Catalysts X-Z are comparison catalysts which comprisemore than 10% added alumina, i.e., 15% by weight added alumina. Thepropylene yields for each of the above-mentioned catalysts weremeasured. These results show that even though the comparison catalystshad suitable DI attrition numbers, they did not benefit from theinvention's higher activities. These examples illustrate the advantageof catalysts comprising about 10% or less added alumina.

[0119] Catalysts AA-CC of Table 11 comprise 70% by weight ZSM-5. Theseexamples illustrate modifying the molar ratio of phosphorus to totalalumina in order to obtain suitable DI attrition, as well as maximizeactivity for the particle.

[0120] Catalysts DD-GG are additional examples of the inventioncomprising about 75-80% by weight ZSM-5. TABLE 10 Invention InventionComparison R S T U V W X Y Z Formulation ZSM-5 60 60 60 60 60 60 60 6060 P₂O₅ 12 14.5 16 14 16 18 15 18 21 Al₂O₃ 2 2 2 2 2 2 2 2 2 Clay 2118.5 17 17 15 13 10 7 4 Aluminum chlorhydrol 5 5 5 7 7 7 13 13 13 Total100 100 100 100 100 100 100 100 100 Physical Properties 2 hrs @ 1000 F.11 8 4 10 4 7 7 9 2 DI Al₂O₃, wt % 18.73 17.80 17.13 19.48 18.62 17.7921.49 20.82 20.07 P₂O₅, wt % 12.10 14.67 16.20 14.25 16.14 18.08 15.6018.08 21.78 SiO₂, wt % 67.41 65.86 65.11 64.78 63.85 62.71 60.31 61.0357.96 P₂O₅/Total Al₂O₃ 0.46 0.59 0.68 1.10 1.26 1.42 0.52 0.62 0.78 SA,m²/g 219 199 174 224 200 177 238 237 243 Propylene Yield Relative to 76%86% 62% 45% 68% 45% 24% 21% 24% OlefinsMax Compared on an Equal ZSM-5Level

[0121] TABLE 11 AA BB CC Formulation ZSM-5 70 70 70 P₂O₅ 9 11 13 Al₂O₃ 22 2 Clay 13 11 9 Aluminum chlorhydrol 6 6 6 Total 100 100 100 PhysicalProperties 2 hrs @ 1000 F. 40 16 7 DI Al₂O₃, wt % 21.34 19.02 17.93P₂O₅, wt % 11.51 11.79 14.22 SiO₂, wt % 65.83 67.46 80.88 MolarP₂O₅/Total Al₂O₃ 0.39 0.45 0.57 SA, m²/g 217 238 234 Propylene YieldRelative to 48% 63% 63% Olefins Max Compared on an Equal ZSM-5 Level

[0122] TABLE 12 DD EE FF GG Formulation ZSM-5 79.5 78 76.5 79 P₂O₅ 12.514 15.5 14 Al₂O₃ 3 3 3 2 Aluminum chlorhydrol 5 5 5 5 Total 100 100 100100 Physical Properties 2 @ 1000 0 3 0 0 DI Al₂O₃, wt % 14.42 13.3812.64 11.42 P₂O₅, wt % 13.96 14.53 15.54 14.67 SiO₂, wt % 67.88 71.0567.42 69.6 Molar P₂O₅/Total Al₂O₃ 0.70 0.78 0.88 0.92 SA, m²/g 246 248221 243 Propylene Yield Relative to — — — 100% OlefinsMax Compared on anEqual ZSM-5 Level

Example 15 Attrition of Prior Art Additive

[0123] An example of a catalyst described in WO 98/41595 was reproducedto determine its attrition.

[0124] To an aqueous slurry containing 1,497 g of ZSM-5 (26:1 molarratio of SiO₂ to Al₂O₃) (dry basis) and 5,533 g of water was added 1,122g of clay (dry basis), 449 g of phosphoric acid (86.2% H₃PO₄), 823 g ofan aqueous alumina slurry containing 12.4% by weight alumina (Condea)with 0.2 parts formic acid added per part alumina, and 2,498 g of a 40%Nalco silica sol. The resulting slurry was mixed until smooth andhomogeneous. The slurry was then spray dried in a Bowen spray-drier atan outlet temperature of 350° F. The resulting spray dried product wasthen air calcined for two hours at 1000° F. and analyzed for ICP, t-plotsurface area and DI attrition. Physical Properties 2 hrs. @ 1000° F. 61DI Al₂O₃, wt. % 17.05 P₂O₃, wt. % 7.33 SiO₂, wt. % 73.74 Total SurfaceArea 152

[0125] The results above indicate the difficulty in obtaining suitableattrition resistant materials when preparing zeolite content catalysts.

What is claimed is:
 1. A catalyst comprising (a) about 30 to about 85%by weight zeolite having a constraint index of 1 to 12, (b) about 6-24%by weight phosphorus, measured as P₂O₅, and (c) alumina, wherein addedalumina is present in an amount of less than about 10% and total aluminais less than about 30%, by weight of the catalyst, said catalyst furthercomprising a molar ratio of phosphorous to total alumina sufficient toobtain a Davison attrition index for the catalyst equal to or less thanabout
 20. 2. A catalyst according to claim 1 comprising greater thanabout 60 to about 85% ZSM-5.
 3. A catalyst according to claim 2 whereinthe phosphorous (P₂O₅) to total alumina molar ratio is at least 0.2 toabout 1.9.
 4. A catalyst according to 3 wherein the catalyst has anattrition index of about 10 or less.
 5. A catalyst according to claim 2wherein the added alumina (c) is present in an amount ranging from about5 to about 10% by weight.
 6. A catalyst according to claim 1 comprisingabout 30 to about 60% ZSM-5.
 7. A catalyst according to claim 6 whereinthe molar ratio of phosphorous to alumina is about 0.2 to about 1.0. 8.A catalyst according to claim 6 where the added alumina is present in anamount ranging from about 3 to about 8% by weight.
 9. A catalystaccording to claim 8 further comprising clay.
 10. A catalyst accordingto claim 7 wherein the catalyst has an attrition index of about 10 orless.
 11. A process for preparing a catalyst comprising (a) preparing aslurry comprising zeolite having a constraint index of 1 to 12,phosphorus-containing compound and alumina, where the alumina is lessthan about 10% by weight of the total weight of the zeolite,phosphorus-containing compound, alumina, and any optional components,and (b) spray drying and calcining the resulting slurry to produceparticulate having a DI attrition index equal to or less than 20 andhaving total alumina content of less than about 30% by weight.
 12. Aprocess according to claim 11 wherein the added alumina is present inthe slurry of (a) in a range of 3-8% by weight.
 13. A process accordingto claim 11 wherein the zeolite is ZSM-5 and is present in the amount ofabout 30 to about 85% of the total weight of ZSM-5, the phosphoruscompound, alumina, and any other optional components.
 14. The productprepared by the process of claim
 11. 15. A process for chemically andcatalytically reacting a hydrocarbon feed comprising contacting the feedat catalytic reactive conditions with a catalyst comprising (a) about 30to about 85% by weight zeolite having a constraint index of 1 to 12, (b)about 6-24% by weight phosphorus, measured as P₂O₅, and (c) alumina,wherein added alumina is present in an amount of less than about 10% andtotal alumina is less than about 30% by weight of the catalyst, saidcatalyst further comprising a molar ratio of phosphorous to totalalumina sufficient to obtain an attrition index for the catalyst equalto or less than about
 20. 16. A process according to claim 15 whereinthe catalyst comprises greater than about 60 to about 85% ZSM-5.
 17. Aprocess according to claim 16 wherein the catalyst consists essentiallyof (a), (b), and (c).
 18. A process according to claim 15 wherein thecatalyst comprises about 60 to about 70% by weight ZSM-5.
 19. A processaccording to claim 15 wherein the catalyst comprises about 40-60% byweight ZSM-5.
 20. A process according to claim 16 wherein thephosphorous to total alumina ratio is about 0.2 to about 1.9 and thecatalyst has an attrition index of about 10 or less.
 21. A processaccording to claim 18 wherein the phosphorous to total alumina ratio isat least 0.45 to about 1.0 and the catalyst has an attrition index ofabout 10 or less.
 22. A process according to claim 19 wherein thephosphorus to total alumina ratio is about 0.25 to about 0.7 and thecatalyst has an attrition index of about 10 or less.
 23. A processaccording to claim 19 where the added alumina of (c) is present in anamount ranging from about 3 to about 8% by weight.
 24. A processaccording to claim 23 wherein the additive further comprises clay.
 25. Aprocess according to claim 15 further comprising recovering ethyleneand/or propylene from said process.
 26. A process according to claim 15wherein the process is fluidized.
 27. A process according to claim 26wherein the process is fluidized catalytic cracking of hydrocarbons. 28.A catalyst composition comprising a large pore aluminosilicate and 0.1to about 90 weight % additive comprising (a) about 30 to about 85% byweight zeolite having a constraint index of 1 to 12, (b) about 6-24% byweight phosphorus, measured as P₂O₅, and (c) alumina, wherein addedalumina is present in an amount of less than about 10% and total aluminais less than about 30% by weight of the total additive, said additivefurther having a molar ratio of phosphorous to total alumina sufficientto obtain an attrition index for the additive equal to or less thanabout
 20. 29. A catalyst according to claim 28 wherein the additivecomprises greater than about 60 to about 85% ZSM-5.
 30. A catalystaccording to claim 29 wherein the additive consists essentially of (a),(b), and (c).
 31. A catalyst according to claim 28 wherein the additivecomprises about 30 to about 60% ZSM-5.
 32. A catalyst according to claim31 wherein the additive comprises about 3 to about 8% by weight addedalumina.
 33. A catalyst according to claim 32 wherein the additive hasan attrition index of less than
 10. 34. A catalyst according to claim 2wherein the catalyst consists of essentially (a), (b) and (c).